Eminent physicist Savas Dimopoulos along with his pals (Howe, March-Russell, Scoville) argue that the LHC data don't imply that the superpartners – new elementary particles implied by supersymmetry – have to be as heavy as usually assumed. Instead, they may be rather light and such a theory yields predictions that are compatible with the LHC data – so far compatible with the Standard Model – anyway.

A possible reason why it may be hard for the collider to see SUSY is known as "compressed spectra". What does it mean? There are always some superparticles that are predicted to be produced rather often (if they're light enough). Why aren't they seen? Because they decay into products (including the lightest superpartner, the LSP, at the end) which have nearly equal masses (approximate degeneracy) which is why little energy is left for the "missing transverse energy".

And Savas et al. are proposing a clever microscopic explanation why the spectra might be compressed. Extra dimensions. They mean pretty large dimensions – much larger than the usual Planck length but much smaller than a millimeter, extra dimensions comparable to the size of a nucleus (or larger than at least 10% of a fermi, the nuclear length scale).

With such large dimensions, the momentum in the extra dimensions is "nearly continuous" which is why from the four-dimensional viewpoint, the spectrum of the new particles' masses is a discretuum, i.e. a very dense spectrum that almost resembles the continuum. With such a discretuum, pretty much any new superparticle X is rather likely to decay to a momentum mode of the LSP whose mass is just a little bit smaller than the mass of X. And the missing-energy signatures will therefore be missing. I mean suppressed or hard-to-see. Missing missing-energy signatures may sound too complex to some readers.

Generic SUSY spectra with a stop that decays to a simple LSP now require \(m_{\tilde t}\gt 700\GeV\) or so, a pretty heavy stop squark (with some other loopholes I don't want to discuss). However, with the new large extra dimensions (yes, Savas is a co-father of the the ADD large extra dimensions models), the data only imply that the stop is heavier than \(350\) or \(400\GeV\). With these extra dimensions, the LHC data don't constraint the sleptons at all.

The fundamental gravitational scale \(M_*\) is meant to be comparable to \(10\) or \(100\TeV\) – a rather natural scale "right above" the LHC, you might say, but a scale that has never been looked for in the usual searches for the extra dimensions. For example, you may be sure that the sub-millimeter gravitational experiments can't get to the nuclear distance scale. However, \(M_*\) could be as high as an intermediate scale \(M_*\sim 10^9\GeV\).

This general scenario might agree with some of the braneworlds in string theory where SUSY is broken on the non-MSSM brane(s).

Tommaso Dorigo's disrespect towards modern physics

I decided to publish this blog post when I saw Tommaso Dorigo's 11. Hide It In The Bulk. He says that according to a T-shirt, physicists who face problems because all of their other methods fail have to do one of the 10 things below:

Manipulate the data

Wave hands a lot, speak with a strong accent

Invoke the Anthropic Principle

Recall the success of the SM

Blame it on the Planck scale

Throw it on the lattice

Invent another symmetry

Set all fermion masses to zero

Add heavy fermions

Subtract Infinity

And as you may have understood, Dorigo proposes to add a new line to the T-shirt, "11. Hide it in the bulk". He tries to mock the paper – and apparently all papers on new physics – and calls it "science-fiction" that contradicts Occam's razor.

Well, the difficulty with Dorigo's mocking efforts is that some or many of these qualitative proposals may be right and some of them are supported by rather nontrivial evidence that they may be right. Many insights that are established by today used to be new sometime in the past – and mocked by some of the older clones of a Dorigo. Some of the models are supported by stronger evidence, some of them are supported by weaker evidence.

The T-shirt with the 10 solutions above may be funny because it combines random confused states of physicists. But if you want to interpret it seriously, it is a damn stupid mixed bag of situations that have nothing to do with each other. The manipulation with the data is usually fraud – well, in some cases, one may correct errors in the data in this way, but one must have some good luck plus other good conditions.

Waving hands and accents are just funny but they don't really carry any physics idea.

On the other hand, the anthropic principle is an idea that has been proposed to be relevant for physics and it needs to be argued about and evaluated using physical arguments that the likes of Dorigo don't even want to consider. The status of the anthropic principle is "open" at the sociological level – although I will of course tell you why all of its existing versions are wrong.

On the other hand, the success of the Standard Model and the fact that at least some differences and surprises are caused by the existence of the Planck scale – i.e. by the existence of gravity – are indisputable facts. Lattices are clearly useful and legitimate methods in physics. Well, sometimes they are useful, sometimes they are less useful; the devil is in the details. And symmetries are important principles – and every symmetry we use today was new at some moment in the past which also suggests that every symmetry that is new now has a chance to be established in the future.

Both heavy fermions and the massless limit of the fermions are important limiting situations to consider and physics can derive important qualitative implications of both assumptions. Some of these derived claims are right, some of them are wrong. Infinities have been subtracted on a daily basis for 70 or 80 years and the process works great – unless one does it incorrectly. We've known why it works so great for over 40 years, too.

Finally, things may demonstrably hide in the bulk. It is an elementary fact of any physical model that contains the "bulk" that the "bulk" has some different properties than the branes or the boundaries. Certain things are more visible in the bulk, others are less visible, and so on.

The fact that all of these eleven diverse ideas and circumstances (each of which includes hundreds of inequivalent particular claims whose truth value may differ from the rest, too!) appear on the same meant-to-be-funny shirt doesn't mean that their status is the same. It certainly doesn't mean that an intelligent person may mock all of them. Everyone who just mindlessly mocks them is a low-energy, low-brow, low-status idiot resembling Tommaso Dorigo.

Everyone who is at least 20 IQ points smarter than Tommaso Dorigo knows that there are lots of very intriguing and potentially powerful arguments in this paper – or at least many other phenomenological papers on new physics that have been written. An honest physicist simply can't ignore them. An intelligent physicist can't consider all ideas about new physics to be science-fiction.

It's bizarre when such attitudes are displayed by someone who is employed as an experimental physicist. The very purpose of the occupation is to decide which of the new ideas are right and which of them are wrong, to direct the search. It is necessary to emphasize that the experiments are not the only considerations that direct the progress. There are lots of top-down arguments that help to determine how much time competent model builders spend on one class of ideas vs another class of ideas. For example, there are lots of top-down rational reasons to think that supersymmetry gets unbroken at a high enough energy scale.

If the experimenters don't find anything new (e.g. for the next 20 years), well, we will survive. Null results also carry some information value. It's just less interesting information. I would find it surprising why people would become experimenters if they were convinced that they may discover nothing new. Maybe most students in Italy only become experimenters because they view the field as a nonsensical human activity that is actually a good welfare system where one doesn't have to do much and gets a lot.

But the people who are doing experimental physics for meritocratic reasons – who think that their work is meaningful – do share the "belief" or "world view" that some ideas will turn out to be right and they want to contribute to the separation of the right ideas from the wrong ones. To use the phrase science-fiction for all potentially good ideas is just stupidity – something utterly incompatible with the very purpose of science.

What Dorigo calls "science-fiction" is actually called "science". Papers like this new paper by Savas and pals are really science at its best. They connect some principles extracted from previous experiments and previously overlooked possibilities to find some new possibilities that were being overlooked as recently as yesterday, and extract completely well-defined (and general enough as well as particular enough) observable implications out of these assumptions. These papers map the space of possible theories and ideas and they compare this space with the real world we know from the empirical data.

There is nothing "obviously unnatural" about these ideas. Top-down arguments generally imply that "some extra dimensions" exist and their size is unknown. Near-Planckian extra dimensions may be preferred for some (mostly top-down) reasons, very large dimensions for other (mostly bottom-up) reasons, but the intermediate size isn't really ruled out and must be considered as a possibility. Such intermediate-size extra dimensions require the Standard Model on a brane and the rest of the conclusions by Savas et al. is almost guaranteed, a robust consequence of very mild assumptions.

So such papers don't really violate any "Occam's razor". They are only in conflict with the stupidity of aggressive morons such as Tommaso Dorigo who like to "cut" everything that transcends the capabilities of these marginal primates. They may use such razors every day to cut pieces of pork off their bodies. But unlike Dorigo, legitimate scientists are able to check and see that the text by Dorigo is a foul play, a stupid rant for stupid readers that doesn't contain any scientifically tolerable evidence in one way or another.

This "Occam's razor" may be good enough for Dorigos to cut many pounds of the pork off their bodies but it – mindless mocking of very serious and rather clever papers – isn't compatible with science. So: vaffanculo, Dorigo!

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12. Load an Eötvös experiment with geometry, below. (Display the picture in a new tab.) One vertical plane of gold-plated four test masses is single crystal alpha-quartz, space group P3(1)21. All atoms are in right-handed 3-fold helices. The opposite vertical plane is space group P3(2)21, left-handed. A total 40 gram loading opposes 6.68×10^22 pairs of opposite shoes (pairs of 9-atom 0.113 nm^3 volume enantiomorphic unit cells).

Not denigrating the skill and importance of experimental physicists, but the last experimentalist with the intellect of a great theorist was likely Fermi, and the last theorists who was also a gifted experimentalist was Newton :)

Yes, all of this could be true; although extra dimensions on atomic scale that so far have gone unnoticed seems like a stretch to my admittedly amateur perception of these matters.That said, overall I do agree with the remark about occams razor. Ive said as much before; if this tower of babel of novel ideas and concepts turns out to be true (And yes, I suppose it might), it truly would be a paradigm shift. Historically, the ratio of directly available novel data to bold theoretical leaps has been orders of magnitude more modest, for successful discoveries.

Personally, id much rather bet on completely out-of-the-box ideas to provide the elegance and unification we are looking for, than for this paradigm shift to occur. Either way, the odds of any one particular unproven theory being proven correct eventually, are always very low indeed.

I think,every one will agree with the statement on Fermi. But from what I have heard, " the last theorist who was also a gifted experimentalist" was Lord Rayleigh. May be someone can verify or contradict this!the latst theorist who was also a gifted experimentalist

Dear John, 20 IQ points is exactly equal to 4/3 of a standard deviation of the - by definition - normal distribution of IQ in the whole population. It's a significant enough difference to separate high-energy theoretical physicists from those who edit slogans for T-shirts.

Can you give me a comparable satisfactory answer to the question what does "a lot" mean? It may be my signature phrase but I haven't used it more than 5 times which is not "a lot" in my vocabulary, especially not when understood in the context of 6,000 blog posts.

Even 10-micron-large extra dimensions could have gone unnoticed - adequate models with them make predictions compatible with everything we have observed - as long as we are localized in these large dimensions, i.e. in the braneworlds. The Standard Model particles may only move along the usual 3+1 dimensions - plus much smaller extra dimensions if they exist - and only gravity (plus some other "similar" new fields) feels all of the spacetime geometry.

It is always very questionable if someone argues that something looks like a stretch, without having a technical reason "why". In too many cases, it's just a mindless opposition to all new ideas and previously overlooked possibilities.

Do you understand why talking about "completely out-of-the-box ideas" looks largely ill-defined to me? It's a talk about some ghosts. The very purpose is to make the phrase sound mysterious. But science ultimately is not mysterious. So I don't really see why e.g. fermi-sized extra dimensions are not "out-of-the-box". Is there a more objective way to determine what is "out-of-the-box" than to ask you personally? Can you enlighten me?

Yes, I am talking of this former post: "By this logic we can exclude models with very low Kaluza-Klein scales, i.e. models of large extra dimensions." (http://motls.blogspot.com.br/2014/03/bicep2-primordial-gravitational-waves.html)

I have no problem with extra dimensions, and indeed they are a cool out-of-the-box idea; but to postulate that the known particles are localized in these extra dimensions seems highly arbitrary; and highly convenient.

Ideally, an out of the box idea makes things simpler right away; rather than requiring a highly inelegant Band-Aid to explain away all of its detectable implications right away, which is kindof the other extreme. Do you have an example of physics or science ever proceeding in that way?

So I have no particular opposition to extra dimensions, but my point is that this is just one out of an infinite number of out-of-the-box ideas; and every single one of them has a very tiny chance (historically speaking) of turning out to be correct.

Thanks for your answer. I don't know how many times you have used it but whenever I saw you say "if IQ of him was x points larger" x was always 20. So a lot is meaningful in the set of sentences like "if IQ of him was x points larger". Of course it is not meaningful in all blog posts.

For example, I remember you saying it for Peter Shor. You have said for Freddy Cachazo :"Or reduce his IQ by 20 and switch from exact novel expressions for scattering amplitudes to Neil Turok's superficial childish models of the cyclic universe "

By the way the answer you have given was exactly kind of answer I was expecting. I hope my answer also satisfied your expectations. I don't know why it is bothered you.

You maintain tons of typical layman misunderstandings who have no (technical) clue about theoretical physics and how it or science generally proceed.

Not all crazy cranky "out of the box" ideas made up by surfer or biker dudes, armchair philosophers, or other wannabees are equally valid or equally good! Physicists and people in the know appreciated that new ideas have to meet certain (consistency among other thinsgs) criteria, so what the authors of the paper suggest does only seem "random", "arbitrary" or whatever similar term to disparage it you would like to sling around, to people who have no clue about theoretical physics and should therefor shut the f*** up about such advanced topics !

Dear Eelco, the claim that "the localization of known particles in extra dimensions is arbitrary" only shows that you have no clue about physics.

It is as wrong as the claim that 6+9 = 15 is unbelievable or contrived. The solutions of string theory - and even low-energy effective field theories - simply do have branes and they do naturally carry matter spectrum analogous to or generalizing the Standard Model.

It's bullshit that "out of the box ideas have made physics simpler right away". All "out of the box ideas" have always made physics more complicated for the people who didn't want to learn new physics. Newton forced legitimate physicists to learn calculus which wasn't simpler. Maxwell and others forced legitimate physicists to learn partial differential equations etc. which were even harder, and they became nonlinear in general relativity.

Special relativity introduced mixing of space and time which was not - and still is not - simpler for the stupid people. The hardest thing to swallow was quantum mechanics, however, with observables represented by linear operators on a Hilbert space, with a spectrum and the corresponding uncertainty. People find it so "non simple" that some of these folks - including physics PhD - are dreaming about the quantum revolution's being undone even now, in 2014.

So I have no particular opposition to extra dimensions, but my point is that this is just one out of an infinite number of out-of-the-box ideas;

My point is that this sentence of yours, much like virtually everything you keep on writing, is self-evident rubbish. There is a finite - and rather small - number of similar ideas. Extra dimensions are there or not. Their number is 6, 7, or more. The Standard Model is localized or not. The size of these dimensions is near-Planckian, almost macroscopic, or intermediate.

There are just a few qualitative choices of this importance. The number of existing options is clearly finite and manageable, and it will always remain so. Your suggestion that there is an infinite number of these possibilities is only a method for you to show that you are an inadequate crank from the viewpoint of people like me; and a method for yourself to justify your decision not to learn anything and remain an idiot.

I am fully aware that there is a finite number of possibilities as far as extra dimensions are concerned; note that's why i never claimed otherwise. But 'extra dimensions' as a paradigm, is only one out of an infinite number of (mostly as-of-yet-unconcieved) paradigms.

I fully comprehend all the physical topics you discussed here, be it newton or general relativity. And all of these ideas seemed like incredibly explanatory and simple ideas more or less right away to me. I havnt had that epiphany with respect to extra dimensions which-just-so-happen-not-to-be-detectable yet, but it could just be my idiocy speaking.

If you are interested in convincing the village idiot (and of course you have better things to spend you time on), finding testable implications always helps; excuses for why there arn't any testable implications do not. Im sorry, but such is the nature of the simpleton. Don't blame the messenger.

Not all crazy cranky "out of the box" ideas made up by surfer or biker dudes, armchair philosophers, or other wannabees are equally valid or equally good!Phew; good thing I never claimed any such thing then!

I fully appreciate that being consistent with the data is an admirable feat of any theory, and a criterion that precious few theories manage to meet. But given multiple theories consistent with the data, occams razor prefers the simplest one. Again, don't blame the messenger on that one; im just repeating occams words.

Again, elaborate theories that give testable predictions are more 'marketable' than elaborate theories layered with elaborate theories to give reasons as to why there arnt any testable predictions. That's a cruel truth about the world I can attest to, even without claiming to share a shred of your deep understanding of 'advanced topics'.

I guess this puts SUSY and additional large dimensions in the same category as, for instance, double special relativity and related lorentzs-approximating theories, and our dear host will attack these ideas with the same ferocity from now on?

Im not an expert on these matters, but something is telling me such results will do little to redraw the ideological lines.

Obviously you belong to the horde of arrogant pompous their state of knowledge blatantly overreaching fools who feel entitled to troll about topics they have no clue about, omnipresent everywhere these days in not appropriately moderatied places.

I rely on the fact that TRF is properly moderated and this might well be one of your last trolling comments in this thread, so enjoy it as long as you still can ... ;-)

This strikes me as an absence of evidence as evidence play to save natural SUSY. I thought that extra large dimensions had already been "very constrained" now they are trying to ressurect that? That being said I would rather see work on a mathematical justification of why unification options are reduced to ST. That's the best bet right now.

Maybe I should invent a TROLL INDEX, similar to John Beaz crackpot index http://math.ucr.edu/home/baez/crackpot.html, by assigning a certain amount of points to specific words, phrases, and attitudes often displayed in trolling comments in too popular unmoderated places in the internet ...

Random potential entries that come to mind already now are:

- 10 troll points as a bonus to start with- 50 points for claming that the trollking is an authoritative theoretical physicist- 40 points for mentioning the term "testable"- 70 points for mentioning the term "falsifiability" -40 points for using any legitimate theoretical physics term or topic together with the word "religion" in the same sentence ...- etc ...

I will have to think about this (and analyse the typical content of trolling comments) and then post it on TRF :-D

The TROLL INDEX could then even be used by bloggers or owners of a website to customize their spam filter to autodelete trolling about theoretical/fundamental physics comments, LOL :-D

I respect the right of our host to make this as much of an echo chamber as he pleases. It would be somewhat ironic, given my sympathy for the hardship our host has experienced at the hand of The Cathedral for his outspoken and out-of-the-box thinking on socio-political topics, but I suppose comparing being banned from a blog and being banned from a profession is a bit of a stretch.

People please consider that experimentalists cover a whole range of people, particularly in HEP, where each experimental publication has 3000 signatures. I am sure that already bright young physicists are combing the paper trying to see if they could say something with their data. As always in large groups of people the bright pennies are not the average, but they are there.

Yes it is intended to be a service for people who want to keep serious online physics discussions free of trolls, agressive pompous dilettants, cranks, and other vermin without having to spend 24h/day on moderation ....

Happily, the aggressive trolls are very limited in their vocabulary, their typical comments and "arguments" very self-similar, and they behave in a very stereotyp way such that for anybody slightly experienced with basic programming it should be an easy exercise to write a script to delete their nonsense and to automatically ban them ;-)

i was going to suggest some additions to Dilaton TRoll index but I will be serious instead. Everyone has better things to do than convince someone who really doesn't care that they are sounding ignorant. Please poke around this blog and in a couple of years-if you are not really an idiot and not just a troll- you will see why extra dimensions are not extra and why the string model is not just another alternative.

i was going to suggest some additions to Dilaton TRoll index but I will be serious instead.

Thanks. I would say it speaks well of someone and their ideas if they can manage to keep this level of emotional distance between their ideas and themselves.

I have been reading this blog for several years, and it is hardly my only physics education. Yet I concede that you may be right; perhaps if I did know more about string theory, I would place more confidence in it. In fact, I fear this may be all too true. If someone spends the best years of their life entwining their fate with any given theory, nearly everyone will come to embrace it wholeheartedly. Its only human, and perhaps necessary for the development of any theory. On the individual level, science isn't driven by truth, its driven by ego. Its just that given enough time, only the egos that havnt been proven wrong yet will remain standing. I certainly admire people willing to bet their careers and lives' work on the truth or falsehood of any idea that may not even be resolved within their lifetime.

But for what its worth (and yes, I know you think little of it), as judged from a little distance, the signs are not looking too good.

Nope, you are distorting once more what Rehbock said because you obviously cant stop trolling.Rehbock meant when UNDERSTANDING physics yiu would know hwat you are talking about and therefore not keep making an idiotic fool of yourself and insulting science.You mbreathtaking moron have no clue how science works. Ideas are only given up if they are contradicted by experimental or theoretical facts, or they are extended as knowledge deepens.

Randomly claiming that physicists hold who work on beyond the sm physics such as the authors of the paper hold on to ideas that have been disproofed in this ways is among the worst uninformed insulting kind of trolling.

Trolls like you are immune against education and not even an infinite time of reading TRF or trying to learn stuff will obviously change a single thing about your behaving like a hardcore idiot.

I would say that ego is involved in all those human activities. It certainly has been in my own research.

I have quite embarrassed myself in the past, allowing myself to get swept along with the seeming promise of an idea. Its only after the weak points have become undeniably obvious, that I have to wonder why I managed not to see them for so long. There is only a finite number of time, and a finite number of questions that your subconscious may direct your attention to, and as long as there are still positive and exciting questions to explore, the more disillusioning questions remain unexplored. That's how it seems to work for my brain, at least. I hope to get wiser as I get older, but time will tell.

As far as I can see, no one is entirely immune from this dynamic. And as I said, perhaps it has a function. To take CEO's as an example: every entrepreneur that I know has always sounded stupidly optimistic to me, as if they don't know that most startups fail, or at least try their best not to know it. But then again if even you don't believe in your product, who else will? You need this bubble of positive energy to carry your baby through years and years without profitability.

Dear Anna and Dilaton, it may be worse than you think. ;-) The trackbacks pointing to Dorigo's blog are probably being added automatically when he mentions an arxiv.org link.

I learned not to pay attention to these things because the number of people who are led over there is of order one, and much smaller than the number of arXiv.org readers who end up e.g. on my blog through other routes.